This study concerned pre-school programming in public libraries and the impact of such programs on (1) the circulation of children's books and (2) the number of children visiting the library. The hypothesis was that effective programming for pre-schoolers increases the number of children coming to the library, which, in turn, increases circulation. Data from the main library and a branch library for a county system in Las Vegas, Nevada, were compiled over an eight month period, and a positive correlation was found between the two independent variables, increase in attendance and increase in circulation of children's books. Increasing interest in pre-school programs, as evidenced by the growing number of children enrolled, was also studied, and responses to a survey questionnaire showed that parents of participating pre-schoolers were also circulating a greater number of children's and adults' materials. Information gathered during the study confirmed that effective programs enhanced circulation and use of the library. (Author/JAB)